The Aries 10" .5 LB KDF/GAC Water Filter AF-10-2010 is a replacement water filter cartridge that contains KDF and Granular Activated Carbon (GAC). This KDF water filter features oxidation-reduction (redox) media that removes chlorine, hydrogen sulfide and many other contaminants from your water. When KDF is mixed with GAC, it helps extend the life of the filter. KDF also helps GAC work better at removing taste and odor. This GAC water filter cartridge ultimately results in pure, clean, great-tasting water.